parser: fix error handling for period in expressions

Author: mertcandav

std/jule/parser/expr.jule

@@ -945,9 +945,11 @@ impl exprBuilder {
 				f.Exception = self.p.buildScope(blockTokens, rbrace)
 				x.End = rbrace
 			| token::PERIOD:
+				mut t := self.t
 				self.next()
 				if self.eof() {
-					break
+					self.pushErr(t, "expected selector or type assertion")
+					ret nil
 				}
 				match self.t.ID {
 				| token::NAME: